为了在不显著提升计算复杂度的情况下,有效提升通信系统的误码率(BER)性能,利用深度学习在数据处理方面的强大能力,提出一种面向基于蜂窝网络的车联网(C-V2X)通信的基于深度学习的联合信道估计与均衡算法——V-EstEqNet.与传统算法分两个阶段分别进行信道估计与均衡不同,V-EstEqNet将通信系统接收机中的信道估计与信道均衡进行联合考虑,并利用深度学习网络直接对接收数据进行校正和恢复,无须进行显式的信道估计环节即可完成信道均衡.具体而言,首先利用大量的接收数据对网络进行离线训练,使网络学习到叠加在接收数据中的信道特性;然后利用该特性恢复原始的发送数据.仿真实验结果表明,在不同的速度场景下,所提算法可以更加有效地追踪信道特性;同时,相较于传统信道估计算法(最小二乘法(LS)和线性最小均方误差法(LMMSE))配合传统信道均衡算法(迫零(ZF)均衡算法和最小均方误差(MMSE)均衡算法),所提算法在低速环境下有最高有6 dB的BER增益,在高速环境下最高有9 dB的BER增益.

针对传统信号检测算法无法有效应对子载波间干扰问题,提出了一种基于高斯赛德尔算法改进的迭代并行干扰消除信号检测算法.该算法首先利用自适应迭代的高斯塞德尔算法获取待检测信号的粗略估计;然后利用迭代并行干扰消除算法对初始解进行迭代优化,并在迭代过程中引入提前更新机制.仿真结果表明,在长期演进—车联万物通信系统中,该算法的检测性能超过了传统初始解的迭代并行干扰消除算法,逼近最优初始解算法性能.这种算法以较低的计算复杂度达到了较好的检测性能,为长期演进车联万物系统信号检测算法的设计提供新思路.

In the frequency division duplexing (FDD) massive multiple-input multiple-output (MIMO) system, the channel state information (CSI) matrix existed noise caused by the wireless channel interference and the time correlation caused by Doppler shift.Because of these effects, the communication system couldn’t guarantee the requirements of reliability and low delay.An intelligent CSI feedback method was adopted.The convolutional neural network (CNN) and batch normalization (BN) network was used to extract the noise in the CSI matrix and learned the spatial structure of the channel.The time correlation between the CSI matrices through the attention mechanism was extracted to improve the accuracy of CSI reconstruction.The data was generated by the standard fast time-varying channel model simulation to train the network offline.System simulation and analysis show that the proposed method can effectively suppress the influence of noise and extract the time correlation caused by Doppler.Compared with the traditional CSI compression feedback algorithm and CsiNet algorithm, the proposed method has better NMSE and cosine similarity performance.

This article analyzes the difference on the calculation of the crack width of the reinforced concrete flexural member between the code in 2002 and 2010,through example calculation on the crack width of the floor under different loads.Moreover,after summarizing the traits and regular pattern of the change by analyzing the datum,it is observed that the result using the new standard employing the permanent load combination to calculate the maximum value of crack width is less than that calculated with the old standard.In addition,the changing regularity of the value of the calculation on the crack width is almost similar to the range ability of bending moments,and the influence of the reinforcement stress for range ability of the crack width decreases gradually as the ratio of formula Mq/Mk increases.

Based on the engineering practice,two types of reduced scale models with concave slab were tested under short term static load till failure.Experimental studies were taken to learn the failure modes,deformations,supporting capacities and the details of the specimens.The results indicate that the overall deformation of the floors are similar with RC two-way slabs,complex stress regions and weak parts appear at the conjunctions of the ribbon beams or at the conjunctions of the ribbon beam and the lifting beam.Before reaching the ultimate limit states,deflections and widths of cracks of all the specimens have reached the service limits.Significant ＇X＇ plastic hinge lines occurred on the bottom of the slabs,which indicates that the slabs failed in two-way bending,and the ultimate load can be determined by plasticity theory.Compared with the possible characteristic combinations of engineering practice,the cracking loads of the specimens with cold-rolled deformed bars are much higher,which enables the slabs work elastic under service loads.

Two concave slabs were modeled by ABAQUS based on the experimental researches on cold-rolled deformed bar reinforced slabs with concave,comparisons of deformations,steel strains,concrete damages et al between the test and finite element method analysis indicate the modeling analyses are appropriate.The effects of slab thickness,concave area and steel strength on performance of slab were checked,and comparisons of nonlinear FEM analysis between concave slab and normal two-way slab were made.Combined with the analysis results,deformation characteristics and performances of slabs of this type are clarified,and design suggestions are proposed.

Orchids are members of the Orchidaceae family,one of the largest families of flowering plants.Orchids have highly specialized morphological,structural and physiological characteristics,which makes them have the distinct advantages of studying floral development.The advances in the research on molecular biology of orchids floral development are reviewed in this paper.The limitation in the research was analyzed,the suggestion on the future research work was proposed and the further development on molecular biology of orchids was promising.